Longest fortress system anywhere in Europe.

A World War II evacuation tunnel turned into a history display of Croatian state and people.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

A musical instrument played by the sea.

The big toe of this towering monument to a Croatian national hero is worn from years of superstitious rubbing.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

A tiny church on a man-made island in the Adriatic.

An ancient knight and a symbol of the city's freedom.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

This 135-year-old weather station studied the effects of the climate on human health.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

The 19th-century ruins hide deep in an overgrown forest.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

A replica of the Liberty Bell rang daily from West Berlin's City Hall throughout the Cold War.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

A monument to the man who almost killed Hitler.

A restaurant and observation deck built in a unique broadcasting antenna.

Berlin's old airport.

Super-heavy Nazi architectural experiment.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

Where once there was a train station bathroom, there is now this German burger joint.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.